Methyl tert-butyl ether (MTBE) is a widely used additive in oxygenated gasoline that has recently come under environmental pressure. Consequently, the demand for MTBE is likely to decrease in the future, and new uses for MTBE need to be explored. Production of methyl 2,2-dimethylpropanoate (methyl pivalate) via Koch carbonylation chemistry is an attractive option because methyl pivalate has been shown to be a fluid with a much lower ozone-forming potential than many other oxygenated solvents. Semiempirical, Hartree-Fock, MP2, and density functional theory calculations, believed to be the first on this system, indicated that the most energetically difficult step in this chemistry is the decomposition of MTBE to tert-butyl cation and methanol. Specific solvation effects were included in these calculations by inclusion of a small number of explicit solvent molecules, and nonspecific solvation effects were taken into account using a dielectric continuum model.